Re: Turned Capital letter L (pointing to the left, with serifs)

From: Asmus Freytag (t) <>
Date: Mon, 4 Jan 2016 21:08:03 -0800
On 1/4/2016 1:33 PM, Frédéric Grosshans wrote:

I looked all the pages of the 1809 edition of _Theoria motus corporum coelestium in sectionibus conicis solem ambientium_ where Gauss used this notation in pages 80-81. Almost all notations are standard enough to be familiar to any modern (2015) mathematician or physicist, with two exceptions : this "7" symbol and ☊ U+260A ASCENDING NODE (which is still standard in astronomy). The Greek letters in particular have a pretty standard shape, and I don't see why this symbol would be the only geek letter using a fancy cursive shape. Even the Latin letters used standard shapes ( italic, roman, a few capital fraktur).

That said,  I did not spot a tau in the text, while most of the Greek alphabet was used. Could "7" be a standard shape for tau in 1809 Hamburg ?

The problem is that he used capital Tau, which, in most fonts, looks precisely like capital Latin T. So, he used an alternate shape, the cursive one, which would have been familiar to him based on the fact that he probably studied Greek as part of his education, pretty standard subject at the time and even a hundred years later in upper level schools in Hamburg and elsewhere in Germany (and he would have seen and reproduced handwritten forms, not just printed ones).

However, I still think it is a ⦢ U+29A2 TURNED ANGLE

No, an angle would have two straight lines.

A Greek letter has, overall, a much higher probability of being used for a variable than almost any other symbol (the one non-letter symbol (Ascending node) is one that you say is still standard in astronomy - wheras any quick search of the literature of the 19th century shows that no symbol is consistently used for the "avery daily angle".

For all of these reasons, I find the suggestion of U+29A2 unconvincing.



Le lun 4 janv. 2016 21:38, Raymond Mercier <> a écrit :
On further reflection I can well agree that it is tau. The attached images from R. Barbour, Greek Literary Hands, show clearly (scan 3) the large upper case tau in several lines, and in scan 4 in the first and other lines a hooked version of tau. So I withdraw my suggestion of pi.
Sent: Monday, January 04, 2016 7:58 PM
Subject: Re: Turned Capital letter L (pointing to the left, with serifs)
On 1/4/2016 10:41 AM, Michael Everson wrote:
Certainly it does look more like a very common variant of “tau” than “pi”

Variant of uppercase tau?


Received on Mon Jan 04 2016 - 23:09:31 CST

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